In typical data center configurations, each virtual machine (VM) includes a media access control (MAC) address. In turn, these multiple virtual machines couple to and are controlled by a hypervisor. Thus these VMs below a hypervisor all require a unique MAC address. Within a given cabinet, there can be many hypervisor instances that couple into a top of rack (TOR) switch. This switch includes content addressable memory (CAM) tables that store an association of MAC addresses to physical locations, both for the VMs below it, as well as the MACs for all other VMs within a switching domain/huddle, which is a collection of cabinets or other aggregation of a set of servers or other computing resources of the data center.
Due to the limited size of this CAM table, a constraint is placed on the number of VMs that can be supported by a switch in a network topology.